How to play Nonograms

Nonograms are also known by other names, including Paint by Numbers, Griddlers, Pic-a-Pix, Picross, PrismaPixels, Pixel Puzzles, Crucipixel, Edel, FigurePic, Grafilogika, Hanjie, Illust-Logic, and Japanese Crosswords. If you know how to play one of these, then the rules are the same!

Your aim in these puzzles is to colour the whole grid in to black and white squares. At the top of each column, and at the side of each row, you will notice a set of one or more numbers. These numbers tell you the runs of black squares in that row/column. So, if you see '10 1', that tells you that there will be a run of exactly 10 black squares, followed by one or more white square, followed by a single black square. There may be more white squares before/after this sequence.

This is an example of a 15*15 Nonogram. A bigger Nonogram will usually inidicate a harder challenge.

When trying to solve any size Nonogram, look first at the bigger numbers. We will choose to look at the second column, the one with '10 1' in it. There are going to be a total of 11 black squares here, and 4 white squares. Out of a total of 15 squares, we know already that it will be mostly black squares. There aren't that many possibilites here for this combination so let's look at two of them

I have chosen here the two extremes. In the first possibility, the first run of 10 black squares starts on the first square. In the second possibility, the first run of 10 black squares finishes on the 13th square.

We don't know exactly where this run of 10 black squares starts or finishes, but we do know that if it isn't one of these two extremes, if must be somewhere in the middle. So, we can colour in black where the two extremers overlap:

It turns out that we can also do this for some of the other columns:

We can also do the same thing for rows. But, let's look at something else first. Look at the 7th row. This has '2 6' as the clues, but we already have 3 isolated black squares in here already! If we're going to have tow unbroken runs of black squares, two of these must be joined somehow. The only way this can happen is if the 2nd and 3rd squares are joined to make up the '6'. We don't know exactly where the 6 starts and finishes, but we do know that they must be joined. So we can fill in black the squares in the middle.

Looking at this row again, although we don't know where the '6' starts, we do know that it can't extend more than a further two squares to the left. The '2' is constrained as well, so we can start to fill some white squares in here:

We can use similar techniques to fill in more of the black squares. More rows have three isolated black squares, but only two clues. Further, looking at the 8th row, the clues are '5 8', the 5 is constrained by the first black square already there, it must start in the 1st or 2nd square. This allows us to fill some more black squares in:

We continue through the grid like this, we generally fill the black squares in first, and the white squares start to come later. Here is the completed grid: